Tinted contact lenses and a method for their preparation

ABSTRACT

Contact lenses comprising polymeric lens materials in which reactive dyestuffs have been covalently bonded to monomer units of the polymer backbone, said reactive dyestuffs being reactive dyes capable of forming ether linkages with cellulose and reactive with hydroxyl, amino, amido or mercapto groups present in a hydrogel polymer to form the covalent bond therewith. The invention is of particular interest in the area of so-called hydrophilic or &#34;soft&#34; contact lenses, commonly referred to as hydrogel lenses.

This specification is a continuation of application Ser. No. 580,398filed Feb. 15, 1984, which is a continuation-in-part of application Ser.No. 382,973 filed June 1, 1982, now U.S. Pat. No. 4,468,229 which is acontinuation-in-part of application Ser. No. 292,325 filed Aug. 12,1981, now abandoned.

This invention relates to tinted contact lenses and to a method fortheir preparation.

In particular, the invention concerns contact lenses comprisingpolymeric lens materials in which reactive dyestuffs have beencovalently bonded to monomer units of the polymer backbone. Theinvention is of particular interest in the area of so-called hydrophilicor "soft" contact lenses, commonly referred to as hydrogel lenses.

Many of the known methods for tinting or coloring plastic materials areunsuitable for practical coloring of contact lenses, in particular ofhydrophilic contact lenses. For example, those methods whereby acoloring agent is dispersed in a plastic by dissolving or dispersing adye or pigment in a monomer precursor or in the polymer matrix cannot beused to obtain satisfactory water-absorbable materials. This is becausewater induces a migration of the coloring agent within the plasticmaterial and a leaching of the colorant outside of it. This migration,moreover, can be acelerated during heat sterilization treatments ascommonly used with hydrophilic lenses, since the heating process in mostcases expands the polymer matrix. Therefore, the most common method forpreparation of hard contact lenses, in which the lens blanks are tintedor colored, would not be feasible for the preparation of soft lenses.

One alternative approach for coloring plastic materials is the use ofprinting, transfer or coating methods. According to this process, acoloring agent is caused to adhere to the surface of the plastic. Thismethod is also unsuitable for coloring water-absorbable plastics, suchas are used for the preparation of hydrophilic contact lenses. If aplastic material colored by this method is allowed to swell in water,the applied layer of coloring agent does not swell as much as theplastic itself. Consequently, the coloring agent will become dissociatedfrom the surface of the plastic. In any event, a simple transfercoloring method does not obviate the problem of leaching and will alwaysbe limited by the degree of physical adhesion of coloring agent to thesurface.

A number of methods have been disclosed in the literature whereby all ora portion of a soft contact lens is painted or printed using animplement such as a brush. For example, in Contact Lens Forum, volume 3,March 1978, pp. 13-17, a method is disclosed in which the surface of alens is colored by a chemical printing process. This method, however, isnot entirely satisfactory, as it is noted that the color tends to fadeafter several autoclavings.

The use of water-soluble dyes is also unsatisfactory for the preparationof, in particular, soft contact lenses. Water-soluble dyes will leachduring repeated thermal sterilization treatments. Moreover,water-soluble dyes in long term contact with the eye might permanentlystain the ocular tissue. Thus, the method disclosed in the AmericanJournal of Optometry and Physiological Optics, Volume 54, pp. 160-164(1977), "Methods of Tinting Soflens® Contact Lenses," would not providea solution to the problem of preparation of practical tinted softcontact lenses.

In addition to the problems engendered by the use of hydrophilic plasticmaterial for the preparation of these lenses, there is an additionalcomplication introduced by the dimensions of the lens itself.Conventional hard contact lenses, generally prepared from formulationsusing as principal co-monomer methyl methacrylate, are in general fittedwith a diameter which is less than the diameter of the cornea of theeye. It is therefore possible to use a lens which is colored over itsentire extent. In contrast, soft contact lenses are most commonly fittedwith a diameter larger than that of the cornea. Because of this feature,a uniformly-colored soft contact lens would appear quite prominentlyagainst the white sclera of the eye. In order to prepare a naturalappearing contact lens, it would therefore be necessary to have acolored central area and a clear outer perimeter.

As noted in U.S. Pat. No. 4,252,421, the preparation of such lensesleads to difficulties in fabrication. There must be no bleeding of colorfrom the central portion into the outer, clear portion. Colored area andclear area should, moreover, be concentric and easily aligned during thepreparation. Finally, it is essential that there be no leaching of coloreither into the tear fluid or into the sterilization solution.

U.S. Pat. No. 4,252,421 discloses a method for preparation of softcontact lenses containing a tinted central core and an outer lenselement which is usually clear. The colored central core is formed froma tinted button, which in turn is polymerized from a monomer mixturewhich includes a dye as co-monomer. Thus, the water-insoluble dye ordyes are part of the backbone of the polymer. Alternatively, awater-insoluble dye may be added to the co-monomer mixture and thiscombination polymerized, whereby the dye is entrained in the polymermatrix. Due to the insolubility of the dye, it will not bleed or leachfrom the polymerized button. Two methods are also disclosed forfabricating the contact lens. The first method involves polymerizing thetinted button, placing the tinted button in a mold and pouring ahydrogel co-monomer mixture around the tinted button and polymerizingthis mixture. An alternative method for forming the lens is topolymerize the clear outer button initially and then to form acentrally-positioned aperture through the button. The co-monomer mixtureincluding the dye is then placed within the aperture and polymerized.

This method suffers from a number of substantial drawbacks. With respectto the method in which a water-insoluble dye is merely entrained in thepolymer matrix, the difficulties enumerated above will be present. Incontrast to the uniform composition of a conventional hydrophiliccontact lens, the lenses produced according to U.S. Pat. No. 4,252,421are a combination of hard lens and soft or hydrogel lens materials.Moreover, the preparation of these lenses requires a number of separatefabrication and polymerization steps. In addition, lenses of this typemust be specially prepared for each prescription. Therefore, asubstantial inventory must be carried by the dispenser of contact lensesin order to cover the range of prescriptions and colors normallydesired. Finally, the use of combination hard-soft lenses wouldgenerally lead to a wrinkling or crimping of the edge upon hydration,causing discomfort to the wearer.

U.S. Pat. No. 4,157,892 discloses a method for coloring water-absorbableplastic which comprises four steps. The first step is manufacture of acoupler monomer or coupler polymer. A polymerization radical isintroduced into a coupler agent to obtain a polymerizable couplermonomer, from which a coupler polymer may be manufactured. Either of thecouplers obtained in the first step is then copolymerized or polymerizedwith a water-absorbable plastic in the form of a monomer or a polymer inthe presence of a polymerization initiator to produce a water-absorbableplastic capable of developing color. The material thus prepared isformed into an intermediate product having the same dimensions as thoseof the desired final product, such as a water-absorbable contact lens.Finally, the intermediate product is colored by immersion of the lens inan aqueous solution of a diazonium double salt which acts as adeveloper. The immersion is continued for a length of time required tocause the swelling of the intermediate product, thereby allowing thediazo-component to penetrate into the plastic. Then, the solution iscontrolled to optimum pH value for causing a coupling reaction to takeplace and to allow the azoic dye to develop its color on the finalproduct. The production of partially-colored intermediate products ispossible through the application of ultraviolet radiation to thoseportions of the plastic which are not to be colored, whereby thediazo-components on those portions are broken down.

This method again has the disadvantage of being procedurally quitecomplicated. The procedure for preparation of the material in which thecolor is later to be developed must be carried out in a series ofdiscrete steps, and care must be taken that that is no prematuredevelopment of the azoic dye in the lens material. Moreover, the azoicdye precursor is dispersed throughout the lens material, which couldlead to differences in color intensity dependent upon the thickness ofthe lens material. In order to provide colored lenses for a wide varietyof prescriptions, it would again be necessary for the dispenser to keepa large inventory. In addition, it is clear that this method is onlysuitable for use with specially-prepared lens material, including acoupler. Therefore, it would not be feasible to use the method taught inU.S. Pat. No. 4,157,892 with conventional hydrophilic lens materialscurrently in use. Finally, the use of couplers of the type described inthis reference would be likely to lead to polymeric materials ofinferior quality, compared to materials now in use for this purpose.

It is therefore a goal of the present invention to avoid the problemsassociated with the prior art methods. In particular, it is an object ofthe instant invention to provide a method of tinting or coloring contactlenses which can be carried out without the need for complicatedprocedures and specialized equipment. It is an additional object of theinstant invention to provide a method of coloring lenses which can bekept in inventory in an untinted state, or which are already availableon the market and/or have been prescribed to the patient.

Further objects of the invention include the development of a method forpreparing a contact lens which appears completely natural as worn on theeye, i.e., lenses having a central colored portion covering the corneaand clear edges over the part of the lens covering the sclera. It isadditionally an object of the invention to provide contact lenses whichwill retain the color over long periods of time and repeated chemicaland/or heat sterilization treatments. It is a further object of theinvention to prepare contact lenses in a wide range of colors and colorcombinations through mechanically simple procedures.

These and other object can be achieved according to the invention,wherein contact lenses are disclosed comprising polymeric lens materialsin which exoskeletal covalent bonds are formed between reactivedyestuffs and monomer units of the polymer backbone. In particular, theinvention is directed to contact lenses prepared from hydrophilicpolymeric materials such as used for preparation of so-called "soft"contact lenses.

A wide variety of polymers are suitable for use in the preparation ofthe novel lenses. The only requirement is that the monomers contain a atleast one functional group capable of reacting with a reactive dyestuff,either before or after polymerization of the monomers to form thepolymer. Examples of such functional groups commonly present in contactlens materials are the hydroxyl, amino, amide and thio groups, andfunctional derivatives thereof. In addition, a reactive dyestuff canreact with a suitable exoskeletal unsaturation in the polymeric materialor in the unreacted monomer.

The composition of the lens material itself can vary within wide limits,the only requirement being the presence in the monomer mixture of atleast one component which will provide the polymer with the requiredexoskeletal functional groups. Particularly suitable as monomers forthis purpose are hydroxyalkyl esters of polymerizable unsaturated acids,such as acrylic, methacrylic, itaconic, fumaric and maleic acids. Amongsuch esters, hydroxyethyl methacrylate (HEMA) has been used quiteextensively; lenses prepared from such materials are disclosed, forexample, in U.S. Pat. Nos. 2,976,576 and Re 27,401.

The inventive method can also be used to color hard contact lensesprepared from materials which contain at least one monomer providing therequired functional group. A primary example of such a monomer iscellulose acetate butyrate (CAB), currently in use for hard contactlenses.

In general, however, any polymeric material suitable for use in thepreparation of a contact lens can also be used for the preparation ofthe inventive tinted lenses, with the proviso that at least one of themonomeric components which forms the material contains the exoskeletalfunctional group which can react with the reactive dyestuff molecule.Therefore, the instant invention can be employed with a wide variety ofknown polymeric lens materials. This allows for the possibility ofpreparing tinted contact lenses according to the invention from the widerange of materials already available, as well as novel contact lensmaterials yet to be developed or marketed.

In addition to hydroxyalkyl esters of unsaturated acids, the followingmonomeric materials may serve as typical examples of co-monomers whichcan be used in conjunction with monomers providing the requiredfunctional groups: acrylic and methacrylic acids; alkyl and cycloalkylacrylates and methacrylates; N-(1,1-dimethyl-3-oxobutyl) acrylamide; andheterocyclic N-vinyl compounds containing a carbonyl functionalityadjacent to the nitrogen in the ring, in particular N-vinyl lactams suchas N-vinyl pyrrolidone. Moreover, one or more cross-linking agents maybe used, as known in the art, in order to provide a polymeric materialof optimal properties. Examples of such cross-linking agents includetrimethylolpropane trimethacrylate, ethylene glycol dimethacrylate(EDMA) and diethylene glycol bis-allyl carbonate.

Useful reactive dyes according to the instant invention are commonlyreferred to as "reactive dyes forming ether linkages" inasmuch as thereactive group or groups in this known class of dyes react withcellulose to form an ether linkage, as opposed to, for example, an esterlinkage. Such reactive dyes forming ether linkages are generallydescribed in FIBRE-REACTIVE DYES Chapter VI, by W. F. Beech, SAFInternational Inc., New York (1970), incorporated herein by reference.

This class of reactive dyes, known as reactive dyes forming etherlinkages, are believed to react with hydroxyl, amino, amido or mercaptogroups present in the hydrogel polymer network of contact lens materialsprimarily by nucleophilic addition to form a covalent bond therewith.

A wide variety of commercially available dyes, reactive via nucleophilicsubstitution, are suitable for use in the preparation of the inventivecontact lenses. In addition, virtually any desired shade or tint can beachieved through the use of a particular reactive dye or combination ofreactive dyes.

Thus, dyes containing an activated double bond which is able to add to afunctional group external to the polymer backbone can be used accordingto the invention. For example, exoskeletal bond activated by a bridgemember such as an --SO₂ --, --SO-- or --CO-- group are particularlysuitable for use according to the invention. Similarly, dyes withfunctional groups which can undergo addition reactions with exoskeletaldouble bonds of the polymer may be employed.

Among the types of reactive dyes suitable for use according to theinvention, the following general classes may be mentioned: reactive dyescontaining vinyl sulfone precursors, such as β-sulfatoethylsulfonyl,β-sulfatoethylsulfonamido, β-hydroxyethylsulfonyl andβ-hydroxyethylsulfonamido substituents, as well as suitable derivativesthereof; dyes containing acryloylamino, β-chloropropionylamino, andβ-sulfatopropionylamino and related reactive groups; dyes containingβ-phenylsulfonylpropionylamino groups; dyes containing β-sulfato- orβ-chloroethylsulfamoyl groups; chloroacetyl dyes; α-bromoacryloyldyestuffs; and a wide variety of other reactive dyes which have or arebeing developed for use in the dyeing of natural and synthetic fibers,in particular of cellulose and wool and function by nucleophilicaddition. Although there are many examples in the art of the use ofreactive dyestuffs with clothfiber materials, the application of thesedyes to the preparation of tinted contact lenses has not been discloseduntil this time.

Some typical examples of commercially available dyes suitable for useaccording to the invention are listed below:

    __________________________________________________________________________                     Commercial Brand                                                                              Year of                                      Structure        Name      Firm  Introduction                                 __________________________________________________________________________    Dye-SO.sub.2 --CH.sub.2 --CH.sub.2 --O--SO.sub.3 Na                                            Remazol   Hoechst                                                                             1958                                         Dye-SO.sub.2 NHCH.sub.2 CH.sub.2 OSO.sub.3 Na                                                  Levafix   Bayer 1958                                         Dye-NH--OC--CH.sub.2 CH.sub.2 SO.sub.2 C.sub.6 H.sub.5                                         Solidazol Cassella                                                                            1964                                         Dye-NH--OC--CH--CH.sub.2 Br                                                    ##STR1##        Lanasol   CIBA  1966                                         Dye-NHCH.sub.2 OH                                                                              Calcobond American                                                                            1966                                                                    Cyanamid                                           __________________________________________________________________________

Some specific examples of these dyes, taken from the Color Index, Volume5, Third Edition (Second Revision, 1982) include:

    __________________________________________________________________________                                       C.I. Construction                          Commercial Name       C.I. Generic Name                                                                          Number                                     __________________________________________________________________________    REMAZOL                                                                       Black B      HOE, HST C.I. Reactive Black 5                                                                      20505                                      Black RL     HOE      C.I. Reactive Black 31                                  Blue BR      HOE      C.I. Reactive Blue 158                                  Blue 3R      HOE      C.I. Reactive Blue 28                                   Bordeaux B   HOE      C.I. Reactive Red 49                                    Brilliant Blue B                                                                           HOE      C.I. Reactive Blue 27                                   Brilliant Blue R                                                                           HOE, HST C.I. Reactive Blue 19                                                                      61200                                      Brilliant Green 6B                                                                         HOE      C.I. Reactive Blue 38                                   Brilliant Green GGL                                                                        HOE      C.I. Reactive Green 14                                  Brilliant Orange GD                                                                        HOE      C.I. Reactive Orange 15                                 Brilliant Orange FR                                                                        HOE      C.I. Reactive Orange 82                                 Brilliant Orange 3R                                                                        HOE      C.I. Reactive Orange 16                                                                    17757                                      Brilliant Orange RR                                                                        HOE      C.I. Reactive Orange 7                                                                     17756                                      Brilliant Red 5B                                                                           HOE      C.I. Reactive Red 35                                    Brilliant Red 6B                                                                           HOE      C.I. Reactive Red 174                                   Brilliant Red BB                                                                           HOE, HST C.I. Reactive Red 21                                    Brilliant Red F3B                                                                          HOE      C.I. Reactive Red 180                                   Brilliant Red GD                                                                           HOE      C.I. Reactive Red 63                                    Brilliant Red GG                                                                           HOE      C.I. Reactive Red 106                                   Brilliant Violet 4R                                                                        HOE      C.I. Reactive Violet 27                                 Brilliant Violet 5R                                                                        HOE, HST C.I. Reactive Violet 5                                                                     18097                                      Brilliant Yellow GL                                                                        HOE      C.I. Reactive Yellow 37                                 Brilliant Yellow 7GL                                                                       HOE      C.I. Reactive Yellow 57                                 Brown 3G     HOE      C.I. Reactive Brown 16                                  Brown GR     HOE      C.I. Reactive Brown 18                                  Dark Blue HR HOE      C.I. Reactive Blue 89                                   Golden Orange 3G                                                                           HOE      C.I. Reactive Orange 78                                 Golden Orange 4G                                                                           HOE      C.I. Reactive Orange 74                                 Golden Yellow G                                                                            HOE, HST C.I. Reactive Yellow 17                                                                    18852                                      Navy Blue RD HST      C.I. Reactive Blue 20                                   Printing Black G                                                                           HOE      C.I. Reactive Black 14                                  Printing Navy Blue 3G                                                                      HOE      C.I. Reactive Blue 98                                   Printing Navy Blue 3GH                                                                     HOE      C.I. Reactive Blue 98                                   Printing Navy Blue RN                                                                      HOE      C.I. Reactive Blue 121                                  Printing Navy Blue RR                                                                      HOE      C.I. Reactive Blue 122                                  Printing Rhodamine BB                                                                      HOE      C.I. Reactive Red 133                                   Printing Rhodamine BG                                                                      HOE      C.I. Reactive Red 167                                   Printing Yellow 5G                                                                         CFM       C.I. Reactive Yellow 97                                Red B        HOE      C.I. Reactive Red 22                                                                       14824                                      Red 3B       HOE      C.I. Reactive Red 23                                                                       16202                                      Red BBT      FH        C.I. Reactive Red 103                                  Red Violet R HOE, HST C.I. Reactive Violet 4                                                                     18096                                      Rubine GR    HOE      C.I. Reactive Red 170                                   Turquoise FC3A                                                                             HST      C.I. Reactive Blue 91                                   Turquoise Blue B                                                                           HOE      C.I. Reactive Blue 77                                   Turquoise Blue G                                                                           HOE      C.I. Reactive Blue 21                                   Yellow FG    HOE      C.I. Reactive Yellow 42                                 Yellow FHG   HOE      C.I. Reactive Yellow 42:1                               Yellow G     HST      C.I. Reactive Yellow 14                                                                    19036                                      Yellow GGR   HOE      C.I. Reactive Yellow 96                                 Yellow GNL   HOE      C.I. Reactive Yellow 23                                 Yellow GR    HOE, HST C.I. Reactive Yellow 15                                 Yellow RT    HST      C.I. Reactive Yellow 16                                 Yellow RTN   HOE      C.I. Reactive Yellow 24                                 Yellow Brown G                                                                             HOE      C.I. Reactive Brown 30                                  LEVAFIX                                                                       Black E-B    BAY      C.I. Reactive Black 5                                                                      20505                                      Black E-2G   BAY      C.I. Reactive Black 26                                  Black E-RL   FBy       C.I. Reactive Black 17                                 Black GL     FBy       C.I. Reactive Black 7                                  Black P-G    BAY      C.I. Reactive Black 26                                  Black P-3GA  BAY      C.I. Reactive Black 34                                  Black PN-L   BAY      C.I. Reactive Black 42                                  Black P-R    BAY      C.I. Reactive Black 21                                  Blue E-FBA   BAY      C.I. Reactive Blue 170                                  Blue E-3GLA  BAY      C.I. Reactive Blue 113                                  Blue E-3R    BAY      C.I. Reactive Blue 51                                   Blue P-3GLA  BAY      C.I. Reactive Blue 113                                  Blue P-RA    BAY      C.I. Reactive Blue 104                                  Blue P-3RL   BAY      C.I. Reactive Blue 65                                   Blue Green B FBy       C.I. Reactive Green 1                                  Brilliant Blue E-B                                                                         BAY, MBY C.I. Reactive Blue 29                                   Brilliant Blue EB                                                                          ByDB     C.I. Reactive Blue 29                                   Brilliant Blue E-BRA                                                                       BAY      C.I. Reactive Blue 114                                  Brilliant Blue E-FFA                                                                       BAY      C.I. Reactive Blue 181                                  Brilliant Blue E-FR                                                                        BAY      C.I. Reactive Blue 68                                   Brilliant Blue E-2GLA                                                                      BAY      C.I. Reactive Blue 178                                  Brilliant Blue E-R                                                                         FBy       C.I. Reactive Blue 44                                  Brilliant Blue 14G                                                                         BAY      C.I. Reactive Blue 23                                   Brilliant Blue P-3RA                                                                       BAY      C.I. Reactive Blue 166                                  Brilliant Blue P-RL                                                                        BAY      C.I. Reactive Blue 66                                   Brilliant Blue P-RLA                                                                       BAY      C.I. Reactive Blue 142                                  Brilliant Blue PN-L                                                                        BAY      C.I. Reactive Blue 185                                  Brilliant Blue RR                                                                          FBy       C.I. Reactive Blue 12                                  Brilliant Blue RRN                                                                         FBy       C.I. Reactive Blue 24                                  Brilliant Green E-5BA                                                                      BAY      C.I. Reactive Green 21                                  Brilliant Green 3GL                                                                        FBy       C.I. Reactive Green 9                                  Brilliant Green 1B                                                                         FBy       C.I. Reactive Green 2                                  Brilliant Orange E-G                                                                       BAY      C.I. Reactive Orange 63                                 Brilliant Orange E-2G                                                                      FBy       C.I. Reactive Orange 47                                Brilliant Orange P-GR                                                                      BAY      C.I. Reactive Orange 41                                 Brilliant Red E-2B                                                                         BAY, MBY C.I. Reactive Red 41                                    Brilliant Red E2B                                                                          ByDB     C.I. Reactive Red 41                                    Brilliant Red E-4B                                                                         BAY, FNC, MBY                                                                          C.I. Reactive Red 40                                    Brilliant Red E4B                                                                          ByDB     C.I. Reactive Red 40                                    Brilliant Red E-7B                                                                         BAY      C.I. Reactive Red 87                                    Brilliant Red E-BA                                                                         BAY      C.I. Reactive Red 124                                   Brilliant Red E-3BA                                                                        BAY      C.I. Reactive Red 147                                   Brilliant Red E-4BA                                                                        BAY      C.I. Reactive Red 158                                   Brilliant Red E4BA                                                                         ByDB     C.I. Reactive Red 158                                   Brilliant Red E-G                                                                          BAY      C.I. Reactive Red 67                                    Brilliant Red P-B                                                                          BAY      C.I. Reactive Red 80                                    Brilliant Red P-3B                                                                         BAY      C.I. Reactive Red 81                                    Brilliant Red P-5B                                                                         BAY      C.I. Reactive Red 82                                    Brilliant Scarlet E-5B                                                                     FBy       C.I. Reactive Red 38                                   Brilliant Scarlet E-4G                                                                     BAY      C.I. Reactive Red 117                                   Brilliant Yellow E-3G                                                                      BAY, FNC, MBY                                                                          C.I. Reactive Yellow 25                                 Brilliant Yellow E3G                                                                       ByDB     C.I. Reactive Yellow 25                                 Brilliant Yellow E-GA                                                                      BAY      C.I. Reactive Yellow 111                                Brilliant Yellow E-2GA                                                                     BAY      C.I. Reactive Yellow 106                                Brilliant Yellow P-G                                                                       BAY      C.I. Reactive Yellow 63                                 Brilliant Yellow P-3G                                                                      BAY      C.I. Reactive Yellow 49                                 Brilliant Yellow P-3GA                                                                     BAY      C.I. Reactive Yellow 25                                 Brown E-2R   BAY      C.I. Reactive Brown 19                                  Brown E2R    ByDB     C.I. Reactive Brown 19                                  Brown 13R    BAY      C.I. Reactive Brown 3                                   Brown P-3GA  BAY      C.I. Reactive Orange 71                                 Brown 5RL    BAY       C.I. Reactive Brown 4                                  Dark Blue E-2GA                                                                            BAY      C.I. Reactive Blue 167                                  Dark Blue FG BAY       C.I. Reactive Blue 34                                                                     20505                                      Dark Brown P-BRA                                                                           BAY      C.I. Reactive Brown 24                                  Dark Green E-3BLA                                                                          BAY      C.I. Reactive Green 16                                  Golden Yellow E-3GA                                                                        BAY      C.I. Reactive Orange 67                                 Golden Yellow E-G                                                                          BAY, FNC, MBY                                                                          C.I. Reactive Yellow 27                                 Golden Yellow EG                                                                           ByDB     C.I. Reactive Yellow 27                                 Golden Yellow E-GRA                                                                        BAY      C.I. Reactive Yellow 125                                Golden Yellow IR                                                                           FBy       C.I. Reactive Yellow 9                                 Golden Yellow P-G                                                                          FBy       C.I. Reactive Orange 61                                Golden Yellow P-GGA                                                                        BAY      C.I. Reactive Yellow 87                                 Golden Yellow P-R                                                                          BAY      C.I. Reactive Orange 42                                 Green E-FB   FBy       C.I. Reactive Green 17                                 Green E-FBA  FBy       C.I. Reactive Green 20                                 Gray IG      FBy       C.I. Reactive Black 2                                                                     59880                                      Navy Blue E-2R                                                                             BAY      C.I. Reactive Blue 73                                   Navy Blue E-RA                                                                             BAY      C.I. Reactive Blue 120                                  Navy Blue E-4RA                                                                            BAY      C.I. Reactive Violet 23                                 Navy Blue P-RA                                                                             BAY      C.I. Reactive Blue 120                                  Navy Blue P-4RA                                                                            BAY      C.I. Reactive Violet 23                                 Navy Blue P-RRL                                                                            BAY      C.I. Reactive Blue 67                                   Olive IT     FBy       C.I. Reactive Green 3                                  Orange E-3GA BAY, FNC, MBY                                                                          C.I. Reactive Orange 64                                 Orange E3GA  ByDB     C.I. Reactive Orange 64                                 Orange E-5GA BAY      C.I. Reactive Orange 69                                 Orange P-4GA BAY      C.I. Reactive Orange 62                                 Red G        FBy       C.I. Reactive Red 27                                   Red P-GA     BAY      C.I. Reactive Red 119                                   Red Violet E-2BL                                                                           BAY      C.I. Reactive Violet 7                                  Red Violet E-4BLA                                                                          BAY      C.I. Reactive Violet 33                                 Rubine E-BA  BAY      C.I. Reactive Violet 29                                 Rubine E-FB  BAY      C.I. Reactive Red 37                                    Rubine P-FR  BAY      C.I. Reactive Violet 16                                 Scarlet E-2GA                                                                              BAY, MBY C.I. Reactive Red 123                                   Scarlet E2GA ByDB     C.I. Reactive Red 123                                   Scarlet P-RA BAY      C.I. Reactive Red 153                                   Turquoise IGG                                                                              FBy       C.I. Reactive Green 4                                  Turquoise P-BBA                                                                            BAY      C.I. Reactive Blue 105                                  Turquoise P-G                                                                              FBY       C.I. Reactive Blue 95                                  Turquoise P-GA                                                                             BAY      C.I. Reactive Blue 138                                  Turquoise P-GNA                                                                            BAY      C.I. Reactive Blue 138                                  Turquoise Blue E-BA                                                                        BAY      C.I. Reactive Blue 116                                  Turquoise Blue E-G                                                                         BAY      C.I. Reactive Blue 21                                   Turquoise Blue E-4G                                                                        BAY      C.I. Reactive Blue 80                                   Violet P-4R  BAY      C.I. Reactive Violet 17                                 Yellow E-GR  BAY      C.I. Reactive Yellow 82                                 Yellow EGR   ByDB     C.I. Reactive Yellow 82                                 Yellow E-RL  BAY      C.I. Reactive Yellow 26                                 Yellow 4G    BAY      C.I. Reactive Yellow 10                                 Yellow 14G   FBy       C.I. Reactive Yellow 20                                Yellow P-FGA BAY      C.I. Reactive Yellow 42                                 Yellow P-GA  BAY      C.I. Reactive Yellow 83                                 Yellow P-GRL BAY      C.I. Reactive Yellow 50                                 Yellow P-R   BAY      C.I. Reactive Yellow 54                                 SOLIDAZOL                                                                     Black P-R    HOL      C.I. Reactive Black 21                                  Blue P-3R    CAS      C.I. Reactive Blue 165                                  Brilliant Blue FBR                                                                         CAS      C.I. Reactive Blue 53                                   Brilliant Pink BR                                                                          CFM       C.I. Reactive Red 70                                   Brilliant Pink RL                                                                          CFM       C.I. Reactive Red 69                                   Brilliant Rubin RR                                                                         CFM       C.I. Reactive Red 71                                   Golden Yellow GC                                                                           CAS      C.I. Reactive Orange 31                                 Green P-GG   CAS      C.I. Reactive Green 23                                  Navy Blue P-R                                                                              HOE      C.I. Reactive Blue 67                                   Orange G     CFM       C.I. Reactive Orange 32                                Red P-B      HOE      C.I. Reactive Red 80                                    Red P-2B     CAS      C.I. Reactive Red 181                                   Red P-3B     HOE      C.I. Reactive Red 81                                    Red P-8B     HOE      C.I. Reactive Violet 16                                 Scarlet P-R  CAS      C.I. Reactive Red 176                                   Turquoise P-G                                                                              CAS      C.I. Reactive Blue 159                                  Yellow P-5G  CAS      C.I. Reactive Yellow 129                                Yellow P-R   CAS      C.I. Reactive Yellow 130                                LANASOL                                                                       Blue G       CGY      C.I. Reactive Blue 177                                  Blue 3G      CGY      C.I. Reactive Blue 69                                   Blue 3R      CGY      C.I. Reactive Blue 50                                   Orange G     CGY      C.I. Reactive Orange 29                                 Orange R     CGY      C.I. Reactive Orange 68                                 Red B        CGY      C.I. Reactive Red 65                                    Red 5B       CGY      C.I. Reactive Red 66                                    Red G        CGY      C.I. Reactive Red 83                                    Red 2G       CGY      C.I. Reactive Red 116                                   Red 6G       CGY      C.I. Reactive Red 84                                    Scarlet G    CGY      C.I. Reactive Red 178                                   Scarlet 3G   CGY      C.I. Reactive Red 136                                   Scarlet 2R   CGY      C.I. Reactive Red 78                                    Violet 3B    CGY      C.I. Reactive Violet 34                                 Yellow 4G    CGY      C.I. Reactive Yellow 39                                 Yellow 6G    CGY      C.I. Reactive Yellow 126                                Yellow 4R    CGY      C.I. Reactive Yellow 127                                RHODAZOL                                                                      Brilliant Orange YA                                                                        HST      C.I. Reactive Orange 50                                 Dark Blue 2BLA                                                                             HST      C.I. Reactive Blue 89                                   Dark Blue 3GLA                                                                             HST      C.I. Reactive Blue 90                                   Scarlet 3GA  HST      C.I. Reactive Red 94                                    __________________________________________________________________________

The preferred dyes include Remazol Yellow GR (Reactive Yellow 15,Registry Number CAS 60958-41-0); Remazol Turquoise P or RP (ReactiveBlue 21, Registry Number CAS 73049-92-0) Remazol Black B (Reactive Black5, Registry number CAS 17095-24-8); Remazol Golden Orange 3GA (ReactiveOrange 78, Registry Number CAS 68189-39-9); and Rhodazol Brilliant BlueRW.

Another class of Dyes capable of forming tinted lenses in accordancewith the present invention are fluorotriazine dyes. Such dyes react atlower temperatrues than the chlorotriazine dyes, which are notcontemplated by the present invention.

Thus, fluorotriazine substituted dyes, wherein the fluorotriazine moietyis bonded directly, or through a divalent linking group, to the dyestuffnucleus, are reactive at a temperature below about 40° C., to formtinted or dyed contact lenses. Due in part to the high reactivity ofsuch fluorotriazine dyes, the resulting lenses are not subjected todistortion and degradation effects which tend to occur at highertemperatures, and characteristically yield dyed or tinted lenses inwhich the triazinyl moiety is covalently bound to the contact lenssubstrate. Moreover, such dyes or tinted lenses are characterized bytheir level dyeings and tintings, exhibiting good alkaline and acidstability, as well as good stability to light.

Representative fluorotriazine containing dyes are those which are widelycommercially available and include:

C.I. Reactive Yellow 143,

C.I. Reactive Yellow 139,

C.I. Reactive Orange 91,

C.I. Reactive Orange 95,

C.I. Reactive Red 183,

C.I. Reactive Red 184,

C.I. Reactive Blue 182,

C.I. Reactive Blue 183,

C.I. Reactive Blue 184, and

CIBACRON Blue F/GF.

Generally, dyes used in the invention have the formula ##STR2## whereinD is an organic dyestuff radical, L is a bond or a divalent linkinggroup, and X is an optional substituent. Typical structures are those ofthe analogus chlorotriazines (those compounds wherein the fluorine inthe above formula is replaced with chlorine), many of which arespecifically set forth in the Color Index under the heading of ReactiveDyes. While the structures in the Color Index do not limit the scope ofthe invention, they are exemplary of the D,L, and X groups suitable inthe formula above.

Similarly, within the scope of the invention is the use of dyestuffscontaining more than one reactive group capable of forming a covalentbond with hydroxyl, amino, amido or mercapto groups present in thehydroyl polymer network of contact lens materials by nucleophilicaddition.

Preferred reactive dyestuffs capable of forming a covalent bond with thehydroxyl, amino, amido or mercapto groups present in the contact lenshydrogel material are those having the general formulae ##STR3## whereinD is the radical of an organic dyestuff radical;

R is a divalent organic electron attracting group capable of causingelectron withdrawal of the C carbon atoms, thus activating the same;

X is hydrogen or halo; and

Y is a leaving group; or mixtures thereof.

The radical D may advantageously be the radical of an azo,phthalocyanine, azomethine, nitro or anthraquinone dye.

The divalent group --R-- is advantageously bonded directly to anaromatic nuclear carbon of D, or is bonded thereto via an aliphaticgroup such as an alkylene group, e.g., a lower alkylene group. Mostpreferably, --R-- is directly bonded to a nuclear carbon atom of D.

Suitable divalent R groups include --CO--, --SO₂ --, --SO--, --NHCO--,--NHSO₂ --, --SO₂ NH-- and the like. Most preferably, --R-- is --SO₂ --,--SO₂ NH--, --CO-- or --NHCO--.

When X is halo, it is most preferably chloro or bromo.

Suitable leaving groups, Y include --Cl, --Br, --OH, di-loweralkylamino, ##STR4## --SO₂ -phenyl, --OSO₃ ⁻ Z⁺ where Z is a cation,--OSO₃ R₁ or --OSO₂ R₁ where R₁ in each case is alkyl, aryl, aralkyl oralkaryl.

Advantageously where R₁, is alkyl, it is alkyl of 1 to 6 carbon atoms,preferably alkyl of 1 to 4 carbons, including for example, methyl,ethyl, isopropyl, butyl and the like. Where R₁ is aryl, it is preferablyphenyl or naphthyl. Where R₁ is aralkyl, it is preferably lower alkylsubstituted phenyl, such as tolyl or xylyl, and where R₁ is alkaryl, itis preferably lower alkylenephenyl, such as benzyl or phenethyl.

The reactive dyes of the class known as those forming ether linkagesespecially suitable for tinting hydrogel contact lens materials arethose reactive dyes which form a covalent bond with the hydroxyl, amino,amido, or mercapto groups present in a hydrogel polymer network in anaqueous medium having a pH of 9 or greater and a temperature of up toabout 60° C., preferably up to about 50° C., and most preferably up toabout 40° C. Such reactive dyes, especially those of formula (I) or(II), are capable of dyeing hydrogel contact lenses without anysignificant degradation or deformation of the hydrogel substrate, due tothe mild reaction conditions.

The invention provides novel tinted lenses with exceptional colorfastness and color uniformity. According to the requirements in aparticular instance, the dyestuff can be applied to both surfaces of alens or to one surface only. In addition, the lens may be colored onlyin a particular portion or portions of the surface or surfaces. Thus, itis possible without difficulty to prepare lenses with, e.g., coloredcentral portions and clear edges, or with an annular colored portioncorresponding to the iris. The method can also be used, for example, forthe application of identifying indicia on lenses, such as to indicatethe concave or convex surface of a flexible lens.

In general, the formation of a covalent bond between the lens materialand the reactive dyestuff is effected by a simple contacting of thedyestuff formulation, such as a mildly basic aqueous solution, with thelens material until reaction is complete. In a case where both surfacesof a lens are to be dyed, the lens is contacted on both surfaces with aformulation of the reactive dyestuff. The shade of color is controlledby the time of contacting with the dye formulation, as well as thereactivity of the dye with the surface of the lens. When it is desiredto apply the dye to one surface only, or to a specific portion of thesurface, the prepared lens may be placed on a fixture or in a mold, andthe reactive dyestuff formulation applied only to a specific portion orportions of the lens surface. In view of the complicated methodsgenerally employed in the art, this simple mechanical procedure fortinting contact lenses is an enormous advance over the known methods.

Moreover, where desired, deep, fast dyeings can be easily obtained, e.g.such that the lens has a light transmission of 90% or less in thedesired visible color range, and substantially devoid of opacity, overthe colored portion of the lens.

After the reaction of the lens material with the reactive dyestuff iseffected, unreacted dyestuff may be removed using any suitable solvent.The choice of solvent for extraction or rinsing is, of course, dependentupon the solubility of the particular dyestuff. For the majority ofdyestuffs in current use, lower alcohols such as methanol are suitablesolvents. After the cleaning process, the tinted lens is freed of tracesof the solvent, for example by boiling in distilled water.

For economic reasons, it is preferable to treat the already polymerizedmaterial with the dyestuff preparation. However, it would also bepossible to treat a monomer such as HEMA with reactive dyestuff prior topolymerization, and subsequently to polymerize the reactivedyestuff--monomer units.

Because of the formation of a covalent bond between the polymericmaterial forming the contact lens and the reactive dyestuff, the lensesof the invention show a remarkable color fastness to all types ofsterilization treatments commonly used for contact lenses, such aschemical, enzymatic and heat sterilizations. Moreover, since thecoloring material is applied directly to the surface or surfaces of thelens, the shade is independent of lens thickness. This is in markedcontrast to lenses prepared from plastic buttons in which pigment isentrained in the polymer matrix, since, in this case, the intensity ofthe shade is directly dependent upon the thickness of the lens. This istrue, for example, with the contact lenses prepared according to U.S.Pat. No. 4,157,892.

Moreover, since the inventive method allows for the introduction of thecoloring material at any time during the preparation of the coloredlenses, it is possible to tint lenses after filling a particularprescription with conventional clear lenses. Thus, it is not necessaryto keep a large inventory of precolored lenses, a substantial drawbackof many of the known methods for preparing tinted lenses. After fittingconventional clear lenses, the color could be introduced as a final stepbefore dispensing to the patient. Alternatively, previously prescribedlenses could be subsequently custom-tinted according to the desires ofthe wearer. Since the range of polymeric materials suitable for useaccording to the invention is sufficiently broad to embrace virtuallyall lens materials in current use, the inventive method is of an almostuniversal applicability.

Another advantage of the inventive method is the extreme reduction incost of preparation of the inventive contact lenses, relative to knownmethods for preparation of lenses containing at least a central portionwhich has been colored. Suitable fiber-reactive dyes are readilyavailable, and the ease of application of these dyes to the lensmaterials makes unnecessary the use of complicated polymerizationprocedures or equipment.

Tests on the oxygen permeability of lenses treated according to theinvention have shown that there is virtually no change in oxygenpermeability after treatment, as can be seen from the following table:

    ______________________________________                                        Clear Lenses    Tinted Lens (Blue)                                            Oxygen Concentration*(P.sub.L)                                                                Transmittance Oxygen Conc. (P.sub.L)                          (P.sub.o = 6.10)                                                                              (at max. = 587 nm)                                                                           (P.sub.o = 6.10)                               ______________________________________                                        1.       1.68       68.3%          1.71                                       2.       1.47       23.0%          1.50                                       3.       1.56        9.3%          1.51                                       4.       1.66        0.0%          1.60                                       ______________________________________                                         *Tested under same technique as reported by M. F. Refojo, F. J. Holly and     F. L. Leong, Contd. Intraocular Lens Med. J., 3(4) (1977) 27.            

An additional advantage of the inventive lenses is the fact that most ofthe dyestuffs employed for tinting tend to absorb ultraviolet radiation,particularly of the wavelengths shown to be harmful to the eye, forexample in Optical Management, "Ultraviolet Radiation and the OcularMedia," January 1981, pp. 21-33. In particular, it has been reportedthat ultraviolet radiation may be directly linked to the development ofcataracts.

The invention may be better understood through the following examples:

EXAMPLE 1: TOTALLY BLUE ON BOTH SIDES OF TINTED LENS

A stock solution, stable for at least 5 weeks, is prepared by dissolving0.1000 g of a dyestuff of the formula ##STR5## in 10 ml of 0.001 HClsolution. A clear HEMA lens is soaked in 1.0M sodium carbonate solution.The sodium carbonate soaked lens is then placed into 0.11 ml of thestock solution. 4 ml of 1.0M sodium carbonate solution is then added,and the lens allowed to remain in the solution for 53 minutes. Thetinted lens is then neutralized with a buffered saline solution(pH=7.0). Then the tinted lens is extracted, with methanol as a solvent,in a solvent extraction apparatus, until there are no dye moleculesleaching out. This may be readily determined, for example, byspectrophotometer. After the extraction process, the tinted lens isboiled in distilled water for one hour to get rid of any trace ofmethanol. Then the tinted lens is stored in a saline buffer solution.

The transmittance of the tinted lens at wavelength 600 nm is 68%.

EXAMPLE 2: TOTALLY AQUAMARINE ON BOTH SIDES OF TINTED LENS

A stock solution, stable for at least 3 weeks, is prepared by dissolving0.1000 g of a dyestuff of the formula ##STR6## in 10 ml of 0.001M HClsolution. The lens which has been soaked in 1.0M sodium carbonate for 10minutes, is placed into 1 ml of the stock solution. Thus 4 ml of 1.0Msodium carbonate solution is added, and the lens soaked for the desiredtime. The procedures of washing, extracting and rinsing of the lensesare the same as in Example 1.

The transmittance of the tinted lenses at wavelength 670 nm are 80% and70% for two and four hour soakings, respectively.

EXAMPLE 3: TOTALLY BROWN ON BOTH SIDES OF TINTED LENS

Three stock solutions are required for this process, all of which arestable for at least six weeks.

(A) 0.0512 g of a dyestuff of the formula ##STR7## in 5 ml of 0.001M HClsolution.

(B) 0.0574 g of a dyestuff of the formula ##STR8## in 5 ml of 0.001M HClsolution

(C) 0.0291 g of a dyestuff of the formula ##STR9## in 5 ml of 0.001M HClsolution

The lens, which has been soaked in 1.0M sodium carbonate solution for 10minutes, is placed into 0.18 ml of A, 0.12 ml of B and 0.2 ml of C stocksolutions. 1 ml of 1.0M sodium carbonate solution is then added for onehour and allowed to stand. The transmittance of the tinted lens atwavelengths 400, 490 and 605 nm are 45%, 51%, and 60% respectively.

EXAMPLE 4: TOTALLY GREEN ON BOTH SIDES OF TINTED LENS

The lens, which has been soaked in 1.0M sodium carbonate for 10 minutes,is placed into 0.18 ml of solution C and 0.12 ml of solution B preparedaccording to Example 2. Then 1 ml of 1.0M sodium carbonate solution isadded, and the lens allowed to soak in the solution for 30 minutes. Thetransmittance of the tinted lens at wavelengths 580 and 385 nm are 64%and 58%, respectively.

EXAMPLE 5: EDGE CLEAR/ONE SIDE TINTED LENS

The tinting procedures are the same as for the Examples 1-4. The onlydifference is that the clear lens sits in a fixture. A suitable dyesolution is then put into a mold, rather than immersing the lens in thedye solution. The area to be colored only is then brought into contactwith the dye solution. The final steps of the procedure are the same isin Example 1.

Preparation of a fixture suitable for preparing the specific type ofpartially-tinted lens desired is a mechanically simple task. One type offixture found useful for preparing clear-edge lenses may be described asfollows:

The fixture has three interlocking pieces. The bottom piece is a domeupon which the lens is positioned. The curved surface of the dome has adiameter corresponding to that of the lens to be tinted. The top pieceacts as a reservoir for the dye solution and has an elastic gasket. Thisgasket forms a seal on the surface of the lens at the edge of the areato be tinted. The third piece is a housing for the reservoir/gasketassembly. The entire fixture is then inserted in a clamp to hold theassembly firmly in place during the dyeing process.

The lens, which has been soaking in 1.0M sodium carbonate for 10minutes, is placed in position on the dome. The reservoir portion of thefixture is positioned and clamped. The reservoir is filled with thedesired concentration of dye and sodium carbonate solution. The solutionis allowed to remain in contact with the lens until the desired shade isobtained. The reservoir is purged with water until all traces of the dyesolution have been removed. The lens is then removed from the fixture.

Similarly good results may be obtained using, for example, dyestuffs ofthe following structures: ##STR10## Many of these dyes are readilyavailable on the market, and dyes of this type have been known in theart for many years. These examples should be viewed as illustrativeonly, without in any way limiting the scope of the instant invention.

What is claimed is:
 1. A contact lens colored over at least a portion ofits surface, comprising a copolymeric hydrogel material to which atleast one reactive fluorotriazine dyestuff is covalently bonded externalto the polymer backbone by reaction at temperatures up to 60° C. withhydroxyl, amino, amido or mercapto groups present in said polymer, overthe colored portion of the lens.
 2. A contact lens according to claim 1,wherein said reactive dyestuff is covalently bonded by nucleophilicaddition to said hydroxyl, amino, amido or mercapto groups.
 3. A contactlens according to claim 1, wherein said hydrogel material containshydroxy groups in the polymer.
 4. A contact lens according to claim 1wherein the reactive fluorotriazine dyestuff is bonded to the polymerbackbone by reaction at temperatures up to 50° C.
 5. A contact lensaccording to claim 1, comprising a colored central portion and a clearannular edge.
 6. A contact lens according to claim 1, wherein thecolored portion thereof has a light transmission of 90% or less in asegment of the visible light range.
 7. A process for preparing a contactlens colored over at least a portion of its surface, comprising reactingat temperatures up to 60° C. at least one ractive fluorotriazinedyestuff with hydroxyl, amino, amido or mercapto groups present in thepolymeric hydrogel contact lens material, and removing unreacteddyestuff from said lens material.
 8. The process according to claim 7wherein the reactive fluorotriazine dyestuff and the polymeric hydrogelcontact lens material is reacted at temperatures up to 50° C.
 9. Aprocess according to claim 7, wherein said lens material is in the formof a contact lens.
 10. A process according to claim 9, wherein thereaction is conducted in an aqueous medium having a pH of at least 9 andat a temperature of up to 40° C.
 11. A process according to claim 9,wherein the reactive dyestuff is applied to only a portion of said lens.12. A process according to claim 7, wherein said dyestuff reacts bynucleophilic addition to said hydroxyl, amino, amido or mercapto groupsin the hydrogel material.
 13. A process according to claim 7, whereinsaid hydrogel material contains hydroxy groups in the polymer.